Colin Farrell attends the after party for "The Lobster" during the 68th annual Cannes Film Festival

Actor Colin Farrell revealed he was "concerned" for his brother's safety while he campaigned for marriage equality.

The Dublin actor admitted he worried about his older brother Eamon, who is gay, while he was on the campaign trail ahead of last month's marriage referendum

"He campaigned very hard and he put himself out there," Colin said.

"I mean, I was a bit concerned about him, he put himself on the line greatly for a cause that he believes in."

Although Eamon has been married to his long term partner Steven Mannion for years, his movie star brother believes the pair will wed again in their home country now the referendum has been passed.

"I'm sure he will be married [in Ireland] within the next year," Colin said.

Colin Farrell

"He got married in Vancouver seven or eight years ago to his husband, but I think it's time for him to enjoy a homegrown celebration."

The former Ballykissangel star couldn't be happier with the Yes vote and laughed off the No voters' arguments that it was a "dark day".

"It was really funny, because one of the arguments when the vote went through was that the Church came out and said, 'You know, this was a dark day for Ireland,' and all you could see was literally rainbows everywhere," he told E News.

"A dark day in the history of a country with internal civil conflict and war and bloodshed … It was a great day."

Castleknock native Colin has previously revealed in an interview on Claire Byrne Live the bullying he watched his brother suffer.